Electrical vibrator



Juh.7 2, 1940. c. s. wEYANDT ELECTRICAL VIBRATOF.

Filed Nov. l, 1957 INVENTOR @fuk/MMM BY` 9 1/ @fm Xwm Patented July 2, lelie UNITED sTATEs PATENT OFFICE y ELECTRICAL VIBRATOR Carl S. Wcyandt, Pittsburgh, Pa. Application November 1, 1937, Serial No. 172,181

'5 Claims.

vibrator having the vibrating portion mounted so as to vibrate substantially noiselessly.

Another object is the provision of a vibrator having the vibrating portion mounted on a rubber shear spring.

Another object is the provision oi a vibrator operated on the inertia principle in which the vibration oi' the armature is substantially noiseless and is transmitted to the object to be vibrated. v

A further object of the present invention is to provide a vibrator which is oi' simple construction, relatively inexpensive to manufacture, and

which may be operated over long periods of o time without requiring any repairs.

A further object is the provision oi' a vibrator which may be secured to an object to be vibrated and in which the vibration of the armature is maintained substantially in alignment with the pole axis.

Still -another object is the provision of a vibrator operated by current impulses separated by substantial zero intervals and in which the vibrating element and spring elements upon which itl is mounted has a natural or `free periodicity lower than the recurrence periodicity of the current impulses. v

A further object is the provision of a vibrator having the vibrating portion mounted on non- !nagnetic spring elements.

Another object is the provision oi' a vibrator adapted to be operated directly by alternating current, or by a rectified wave developed through astatic rectifier in an alternating current circuit.

Another'object is the provision of a vibrator operated by current impulses derived from an imperfect static'rectiiier interposed inl an alternating current circuit. the number of rectifier units being such that a substantial inverse cur'` rent would flow in the absence oi any inductsnce in the circuit.

According to the present invention, I provide a vibratoradapted to be secured to an object to be vibrated and an electromagnet mounted thereon, the armature o! the vibrator being connected tained without the disad (Cl. 172-126) A by vibratoryelements to the base which serve to prevent impact of the armature against the base. The preferred type of vibratory element comprises a rubber spring mounted so as to be su-bstantially in a state of shear when the arma. ture is vibrating. The vibratory elements preferably maintain the reciprocation of the armature in alignment with the axis of the electromagnet.' The electromagnet may be supplied directly with alternating currentoi suitable frequency. f i

The invention further contemplatessupplying the vibrator with current impulses separated by l zero intervals, such as'are obtained from a rectifier interposed in an alternating current circuit, the natural periodicity oi' the armature and vibratory element being selected to be about ninety to ninety-five per\cent of therecurrence periodicity of the currentfimpulses, depending on the frequency of the alternating current, whereby the maximum amplitude of vibration is obvantage of sensitivity to disturbing forces that occurs when a stateof resonance exists. I prefer to employ dry disk rectifiers which are imperfect rectiers and use the inductance of the circuit to cut down the inverse current so that a lesser number of disks may be employed than would be needed to supply the same current in a non-inductive circuit., The inverse current also may be cut vdown by cooling the rectier disks in any suitable manner.

'I'he invention will be described in detail in connection with the accompanying drawing wherein is illustrated a preferred `embodiment oi' the invention by way of example, and wherein:

Fig. 1 is a side view partly in section, showing a preferred embodiment of my invention,

Fig. 2 is an endveievation oi Figal, the casing being shown in section,

Fig. 3 is an end elevation of a detail on an enlarged scale,

Fig. 4 is a wiring diagram' showing the vlbrator operated from an alternating current throughl one type of rectifier,

Fig. 5 is a, wiring diagram showing the vibrator operated from an alternating current through a dry disk typeoi rectiiier, and

vber pads 29 and 3I moved or vibrated. A rectangular opening 3 is formed centrally of the base I and receives a laminated electromagnet core 9 substantially in theu shape of an inverted T. The core 9 is secured to the base I by cutting the base in half on its long axis, inserting the core 9 in place, and riveting the two halves and the core together by rivets III passing through the core and central rib 2. The two halves of the base are then reunited by Welding. In this way a very rigid structure is built up in issecurely held to the base I. A cushioning pad II of rubber or other suitable material is placed on the base over the core 9, the core being surrounded by a layer of insulation fabric I2 and a coil I3 of insulated wire wound horizontally surrounds the leg of the core. A pair of clips I4 suitably insulated from the coil are bolted to the base I to hold the wire coil I3 securely in place to the base.

The armature I5 is of laminated construction and is substantially in the shape of a C on its side. The laminated plates of the armature are enclosed by thicker side plates I6 and I1 on either side which extend part way along the legs of the C and beyond the armature proper, all the plates being held in assembled position by suitable rivets I8. Cross bars I9 and 2I having bolt holes 22 therein are positioned between the side plates I6 and I1 and are welded thereto or otherwise secured thereto.

Adjacent each end of the base are two vibratory members indicated` generally by the numerals 23 and 24 serving as spring supports for the armature. As these supports are alike in construction, only one of them will be described in detail. 'I'he supporting member 23 comprises an inverted channel shaped metal strip 21 with a hole 28 bored centrally therethrough, and rubhave one ofitheir respective faces secured to each side of theychannel strip 21 by vulcanization or in any other suitable manner. The pads are right and left hand and the faces thereof are substantially parallel.

Angle strips 32 and 33 are vulcanized to the opposite faces of the pads 29 `and 3| and bolts 34 passing through holes 35 in the angle strips secure the armature supports in place at ODpOsite ends oi' the core 9. The ends of the pads are formed as a fillet to reduce tension on the joint between the metal and rubber at the ends. The armature is secured to the vibratory members by bolts 36 passing through holes 28 in the strip 21 and holes 22 in cross bars I9 and 2l, and by nuts 31 and 33, spacing washers 39 being interposed between horizontal bars I9 and 2I and the tops of channel members 21 to provide the proper air gap between the armature and electro-magnet in assembled position, and the bolts are adjusted so that their heads 4I are not in contact with the base. By reason of the non-magnetic properties of the armature supports 23 and 24 the possibility of the electro-magnetic flux being shunted around the air gap into the armature is eliminated.

When the armature is vibrating the faces of the rubber pads secured to the armature are constrained to move substantially parallel to the faces secured to the base, and consequently the rubber pads are in a state of shear. Rubber in a state of shear or tension has a greater amplitude of movement and longer life than rubber in a state of compression. The resistance of the rub-A ber pads to transverse shear enables them to act as guides to maintain the armature in proper which the magnet core 9 which term includes supports 23 and 24 by alignment with the magnet, thereby obviating the need for additional guide members, and the vibrator can be lused in horizontal, vertical or inclined positions. Thus, a greater amplitude of vibration can be obtained over other known vibratory structures without employing separate guides for the armature. Rubber is representative of a class of materials which have a diiierent modulus of elasticity under compression and under tension and follow a pseudo-harmonic law of vibration. such materials not having the undesirable effects of resonance. the armature is vibrating the amplitude of vvibration is such that the heads 4I of the bolts 39 do not strike the base I, and the armature I5 does not strike the electromagnet core 9. Two striking surfaces or buttons 42 of a hard nonmagnetic metal, such as Stellite or Studite" or the like are welded in suitable depressions in the cast steel base in line with the bolt heads 4I so that if the amplitude of vibration becomes too great due to accidental increase in the supply voltage the heads will strike these hard surfaces. The boltheads 4I also may be coated with Stellite or any similar hard metal, if desired. The non-magnetic metal coating and button prevent shunting of the magnetic flux when impact occurs.

In Fig. 4 there is shown a wiring diagram for a vibrator operated from an alternating current circuit having a .static rectifier interposed therein, whereby the coil receives current pulsations separated by substantial intervals oi zero current. The rectifier shown preferably is of the thermionic type, having an anode and a cathode 51. The transformer 58 supplies current from the alternating current source supplied by wires 41 and 53 through switch 59 for heating the cathode of the tube. The anode of the tube is connected by wire SI to switch 32 and by wire 45 to one end of the coil I3, the other end of the coil being connected by wire 49 through rheostat or variable resistor 5I (which is optional) and wire 52 back to the switch 62 and by wire 93 to the alternating current source. The system has the advantage that a larger amplitude oi vibration may be obtained by a given current input.

When the vibrator is operated by the electrical system shown in Fig. 4 and the armature reciprocates without impact, the vibratory mass, the armature I5 and the supports 23 and 24 preferyibratory portions of `ably has a natural periodicity of vibration at the preferred amplitude less than the periodicity of the current impulses, the preferred periodicity being about ninety to ninety ilve per cent of the recurrence periodicity oi the current impulses and may be as close as ninety eight per cento! the recurrence periodicity of the current impulse without undesirable sensitivity. However, the periodicity may be selected to. as little `as two thirds that of the currentimpulses, if desired. For example. in operating the vibrator by current impulses derived through a rectifier from a cycle alternating current source, I prefer to select the natural periodicity of the armature to be nity four to fifty seven vibrations per second. u The free period of vibration of the armature may be changed readily by replacing the others having the desired thickness of rubber pads so as to have the desired natural period.

I place of the thermionic rectifier shown in Fig. 4, any other suitable type oi rectifier may Ordinarily, when phide, mercury arc or electrolytic types. Inng,

5 I show a wiring diagram employing dry plate rectiers which may be copper oxide, or any other suitable type. 'I'he alternating current source III is connected by wire I6 to one end yof v coil I3 and by wire 48 and switch 50 to one plate 54 of the bank of rectiers, the other plate `60 being connected in series to the corresponding plate 5l of the second rectiiler and so on, the last plate being connected by wire 64 to rheostat or resistor 5I which is connected by wire 49 to the end of coil I3. With this arrangement current impulses separated by z'ero intervals is supplied to the coil I3. The number of rectifier units is less than would be required to supply the desired current in a non-inductive circuit, as the inductance cuts down the inverse current.

In the modication illustrated in Fig. 6, the

base i9 has an electromagnet Il secured thereto constructed similar to electromagnet 9 and having a coil I3 wound thereon. A vibratory member Il constructed exactly like member 24 is secured to the cover 'i5 by bolts 16 and a bolt 'I'I` passing through the central hole of,vibratory,

member 14 is threaded into the C-shaped armature 18. The cover 1I is Secured to the base by bolts 19 passing through lugs Il. In this modiilcation onlyl one vibratory unit 'Il is employed and when the cover is in position the air gap between the armature and electromagnet is predetermined by the spacing washers Il. Any desired number oi' such washers may be used to obtain the desired air gap.

. The vibrators herein described may, if desired, be operated directly by an alternating current oi suitable low frequency. For example, where an alternating current oi' iiity cycles is available the resilient members will be selected to havea free -periodicity oi six thousand vibrations per minute, and with an alternating current of twenty ilve cycles, the i'ree periodicity of the armature would be selected at 'three thousand vibrations per minute. Ii' desired, the vibrators may be loperated to impact, the impacts being transmitted to the object to be vibrated. This may be done by lowering the bolts 3l so that the heads 4I strike the buttons I2 on the base, or, the whole amature may be lowered to reduce the air gap.

What I desire to claim as my invention and secure by Letters Patent is:

1. A vibrator comprising a base adapted 'to be connected to an object to be vibrate'd, an electromagnet carried by thebase, a reciprocable armature adapted to be reciprocated uponactuation of the electromagnet, a central channel member, rubber pads vulcanized by one side respectively to said central member, a plurality oi angle members. the other sides ot saidrubber pads bein! vulcanized to said anale members respectively, means for securing said angle members tothe base, and means for securing said armature to said central channel member.

2. A vibrator comprising a base adapted to be connected to an object to be vibrated, an electro? magnet carried by the base, a reciprocable armature adapted to be reciprocated upon actuation of the electromagnet, a central channel member, rubber pads vulcanizedby one side respectively to said central member, a plurality of angle being vulcanized to said angle membersrespectively, means for securing said angle-members to the bese, bolts securing the armature to said central channel member, the ends of the bolts limiting movement or the armature electromagnet.

3. A vibrator comprising 'a base adapted to be connected to an object to be vibrated, an electromagnet carried by the base, a reciprocable armature adapted to be reciprocated upon actuation of the electromagnet, a central channel member,

rubber pads vulcanized by one side respectively to said Ycentral member, a plurality of angle members, the other sides of said rubber pads toward the members. the other sides oi said rubber pads being vulcanized to said angle members respecx tively, means for securing said angle `members to the base, bolts securing the armature to said central channel member, the ends'of the bolts limiting movement oi the armature toward the electromagnet, and a lhard non-magnetic metal coating on said base substantially in alignment with said bolts to provide striking surfaces.

4. A vibrator comprising a base adapted to be connectedI to an object to be vibrated, an electromagnet carried by the base, a reciprocable armature adapted to be reciprocated upon actuation of the electromagnet, a central channel member, rubberpads vulcanized by one side respectively to Said central member, a plurality of angle members, the other sides oi 'said rubber pads being vulcanized to said angle members respectively, means ior securing said angle members to the base, means securing said armature to said central channel member, and means limiting movement oi.' the armature toward the electromagnet.

5. A vibrator comprising a base adapted to be `connected to an object to be vibrated, an electromagnet carried by the basea reciprocable armature adapted to be reciprocated upon actuation of the electromagnet, rubber bodies having substantialy vparallel -fac'es` extending generally in the direction of reciprocation of the armature secured-by one face to the armature and by the other iace to the base, whereby said faces are moved in shear when said armature is vlbrated.

-and means to periodically energize'said electroimagnet to-reciprocate said armature.

CARL s. wEYANrrr. 

